Not applicable.
The present invention relates to a ladder and, more particularly, to a step ladder adjustable to facilitate use on sloping surfaces.
Step ladders are widely used for tasks such as painting, wiring, and grounds maintenance. Often the surface on which the ladder is to be supported is sloping in, at least, one plane. For example, one common problem encountered by ladder users is reaching a ceiling over a stair. While each step of the stair is horizontal and flat, the slope between successive steps makes the use of a step ladder, with its four spaced apart points of support, impractical or unsafe.
McCrystal, U.S. Pat. No. 6,073,726 discloses a step ladder with adjustable stiles and back legs to facilitate use of the ladder on sloping surfaces. Each of the stiles and back legs of the step ladder can be independently adjusted to facilitate use of the ladder on surfaces that slope in more than one direction. Since the lengths of the stiles or step supporting rails are adjustable, the positions on the stiles of several steps can be adjusted to make the ladder easier to use. While step ladders with individually adjustable legs are very flexible and can be used on uneven surfaces, such ladders are relatively complicated and difficult to use. To set the ladder up on a sloping surface, the ladder must be balanced on one or more points of support while the user independently adjusts the lengths of two or more legs. A latching mechanism is required for each of the legs and for each end of each of the independently adjustable steps or treads, increasing the complexity, cost, and weight of the ladder.
What is desired, therefore, is a step ladder that is of uncomplicated construction and that is easy to set up and use on stairs or other surfaces that slope in a single direction.